“Those that send them to me are generally quite excited, as they claim that these frequently resemble something you wouldn’t expect to find on the rusty, dusty surface of the Red Planet,” he told the Huffington Post. “It’s usually some sort of animal, but occasionally even weirder objects such as automobile parts. Maybe they think there are cars on Mars.”

Shostak said that in these cases, something called pareidolia is typically at play.

Pareidolia is defined as “the imagined perception of a pattern or meaning where it does not actually exist, as in considering the moon to have human features.”

“Recognizing a crab in a landscape filled with wind-weathered rocks is no more surprising — nor more significant — than seeing a winking face in a semi-colon followed by a parenthesis,” Shostak told the Huffingtong Post.